Electrolytic process of reducing metallic sulfids.



No. 782,894. PATENTED FEB. 21, 1905. G. E. BAKER & A. W. BURWELL. ELECTROLYTIC PROCESS OF REDUCING METALLIC SULI'IDS.

APPLICATION FILED JULY 1 1904.

Inventors act on fresh portions of the sulfid.

UNITED STATES Patented February 21, 1905.

PATENT OFFICE.

CHARLES E. BAKER AND ARTHUR IV. BURI/VELL, OF CLEVELAND, OHIO.

ELECTROLYTIC PROCESS OF REDUCING METALLIC SULFIDS SPECIFICATION forming part of Letters Patent No. 782,894, dated February 21, 1905. Application filed July 1, 1904:. Serial No. 214,981.

To all whom it may concern:

. Be it known that we, CHARLES E. BAKER and ARTHUR WV. BURWELL, citizens of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Electrolytic Processes of Red ucing Metallic Sulfide, of which the following is a specification.

According to this process a metallic sulfid or mixture of sulfids is placed in contact with or proximity to the anode of an electrolytic cell containing a molten chlorid. The chlorid -is electrolyzed, and the chlorin freed at the anode reacts on the metallic sulfid, displacing the sulfur and combining with the base. The resulting chlorid then melts, replacing the electrolyte, and is inturn electrolyzed, yielding the metal at the cathode and chlorin to re- Theliber ated sulfur may either be distilled off by keeping the cell at a sufiiciently high temperature or allowed to accumulate as a floating layer on the electrolyte and skimmed off from time to time, or it may be combined with an excess of the electrolytic chlorin to produce sulfur chlorid, which is then driven off.

An apparatus for carrying out the process is shown in the accompanying drawing, in which the figure is a transverse vertical section through the electrolytic cell.

The cell shown consists of an iron vessel 1, the sides of which are provided With a lining 2 of refractory non-conducting material, such as magnesia fire-brick. The opposite sides of the lining have shoulders 2, which support the anode. The bottom 3 of the vessel is bare and constitutes the cathode, the electric conductor 4 being secured to one side of the vessel. The anode shown consists of a number of parallel bars 5, preferably of Acheson gra ph The cover has a porcelain bushing 11, through which passes the terminal post 7, a covered feed-opening 12 for the ore, and an outlet 13 for volatile products.

In using the described apparatus to carry out the process the cell is filled with an electrolyte 14 of a molten chloridfor example, lead chlorid. The metallic sulfidfor example, lead suliidis supported within the electrolyte on a refractory shelf, which is preferably the anode itself, although a separate shelf above or in proximity to the anode may be employed. An electric current is passed through the cell, electrolyzing the chlorid and depositing lead on the cathode, where it accumulates as a molten layer 16,- which may be drawn off through an outlet having a cock 17. The chlorin set free at the anode decomposes the sulfid, freeing the sulfur and combining with the lead to reproduce lead chlorid, which replenishes the electrolyte. The sulfur may be allowed to accumulate as a floating layer 15 on the surface of the electrolyte and then skimmed oif, or it may be volatilized and driven off through the outlet 13. By regulating the supply of the sulfid or the current density so that an excess of chlorin is produced at the anode the sulfur and chlorin may be combined as sulfur chlorid, (S2Cl2,) which is distilled off.

Chlorids of some metals-for example, zinc-are volatile below the melting-point of the metal at atmospheric pressure. In treating sulfids of such metals the chlorid may be maintained in a liquid condition by nearly closing the chlorin-outlet 13 and forcing air into the cell to maintain a superatmospheric pressure upon the electrolyte, or the temperature of the chlorid may be maintained somewhat below that of the molten metal at the bottom of the vessel, to which the heat is directly applied, or the chlorid may be allowed to volatilize and pass through a reflux-condenser opening into the top of the cell.

A chlorid of a metal other than that of the sulfid to be treated may be used as the electrolyte. For example,n1olten zinc chlorid has been employed for the treatment of lead as Well as zinc sulfid. Mixed or complex sulfids may also be treated.

We claim 1. The process of treating metallic sulfids, which consists in placing the sulfid in an electrolyte of a molten chlorid and in proximity to an anode, passing an electric current from said anode through the electrolyte, and causing the electrolytic chlorin to react on the sulid and displace the sulfur, as set forth.

2. The process of reducing metallic sulfids, Which consists in placing the sulfid in an electrolyte of a molten chlorid and in proximity to an anode, passing an electric current from said anode through the electrolyte, causing the electrolytic chlorin to react on the sulfid and displace the sulfur, and melting and electrolyzing the resulting chlorid, as set forth.

3. The process of reducing metallic sulfids,

which consists in placing the sulfid in an elec-- trolyte of a molten chlorid and in proximity to an anode, passing an electric current from said anode through the electrolyte, causing the electrolytic chlorin to react on the suliid and displace the sulfur, melting and electro lyzing the resulting chlorid, and recovering the liberated sulfur, as set forth.

4. The process of reducing metallic sulfids, Which consists in supporting the sulfid within an electrolyte of a molten chlorid and in proximity to an anode, passing an electric current from said anode through the electrolyte, and causing the electrolytic chlorin to react on the suliid and displace the sulfur, as set forth.

5. The process of reducing metallic sulfids, which consists in supporting the sulfid Within an electrolyte of amolten chlorid and over an anode, passing an electric current from said anode through the electrolyte, and causing the electrolytic chlorin to react on the sulfid and displace the sulfur, as set forth.

6. The process of reducing metallic sulfids, Which consists in supporting the sulfid Within an electrolyte of a molten chlorid and upon an anode, passing an electric current from said anode through the electrolyte, and causing the electrolytic chlorin to react on the sulfid and displace the sulfur, as set forth.

7 The process of reducing metallic sulfids, which consists in supporting the sulfid Within an electrolyte of a molten chlorid and upon an apertured anode, passing an electric current from said anode through the electrolyte, and causing the electrolytic ehlorinto react on the sulfid and displace the sulfur, as set forth.

8. The process of reducing sulfids of metals Whose chlorids are volatile beloW the meltingpoint of the metal, Which consists in placing the sulfid in an electrolyte of a molten chlorid and in proximity to an anode, passing an electric current from said anode through the electrolyte, causing the electrolytic chlorin to react on the sulfid and displace the sulfur, melting and eleetrolyzing the resulting chlorid, melting the electrodeposited metal, and maintaining the chlorid in a liquid condition, as set forth.

In testimony whereof We affix our signatures in presence of two Witnesses.

CHARLES E. BAKER. A ARTHUR W. BURWELL.

Witnesses:

FRANK N. SEALAND, GEORGE H. LAPHAM. 

